Problem: Determine how many solutions exist for the system of equations. ${-4x-y = 10}$ ${y = -x+2}$
Solution: Convert both equations to slope-intercept form: ${-4x-y = 10}$ $-4x{+4x} - y = 10{+4x}$ $-y = 10+4x$ $y = -10-4x$ ${y = -4x-10}$ ${y = -x+2}$ Just by looking at both equations in slope-intercept form, what can you determine? ${y = -4x-10}$ ${y = -x+2}$ The linear equations have different slopes. ${1}$ ${2}$ ${3}$ ${4}$ ${5}$ ${6}$ ${7}$ ${8}$ ${9}$ ${\llap{-}2}$ ${\llap{-}3}$ ${\llap{-}4}$ ${\llap{-}5}$ ${\llap{-}6}$ ${\llap{-}7}$ ${\llap{-}8}$ ${\llap{-}9}$ ${1}$ ${2}$ ${3}$ ${4}$ ${5}$ ${6}$ ${7}$ ${8}$ ${9}$ ${\llap{-}2}$ ${\llap{-}3}$ ${\llap{-}4}$ ${\llap{-}5}$ ${\llap{-}6}$ ${\llap{-}7}$ ${\llap{-}8}$ ${\llap{-}9}$ When two equations have different slopes, the lines will intersect once with one solution.